Electronic correlations and partial gap in the bilayer nickelate La3Ni2O7

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Aug. 31, 2024

The discovery of superconductivity with a critical temperature about 80 K in La3Ni2O7 single crystals under pressure has received enormous attention. is not superconducting ambient but exhibits transition at T ∗ ≃ 115 K. Understanding the electronic correlations and charge dynamics an important step towards origin other instabilities. Here, our optical study shows that features strong which significantly reduce electron's kinetic energy place this system proximity Mott phase. low-frequency conductivity reveals two Drude components arising from multiple bands Fermi level. removes component exhibiting non-Fermi liquid behavior, whereas one Fermi-liquid behavior barely affected. These observations combination theoretical results suggest surface dominated by Ni- $${d}_{3{z}^{2}-{r}^{2}}$$ orbital removed due to ∗. Our experimental provide pivotal information for understanding La3Ni2O7. bilayer nickelate was recently shown be high-pressure. Here authors reveal opening partial gap, providing key nature density-wavelike compound.

Language: Английский

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Modulation of the octahedral structure and potential superconductivity of La3Ni2O7 through strain engineering

Science China Physics Mechanics and Astronomy, Journal Year: 2025, Volume and Issue: 68(3)

Published: Jan. 9, 2025

Language: Английский

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Electronic structure of superconducting infinite-layer lanthanum nickelates

Science Advances, Journal Year: 2025, Volume and Issue: 11(4)

Published: Jan. 22, 2025

Revealing the momentum-resolved electronic structure of infinite-layer nickelates is essential for understanding this class unconventional superconductors but has been hindered by formidable challenges in improving sample quality. In work, we report angle-resolved photoemission spectroscopy superconducting La 0.8 Sr 0.2 NiO 2 films prepared molecular beam epitaxy and situ atomic-hydrogen reduction. The measured Fermi topology closely matches theoretical calculations, showing a large Ni d x 2 − y –derived sheet that evolves from hole-like to electron-like along k z three-dimensional (3D) electron pocket centered at Brillouin zone corner. bands show mass enhancement ( m */ DFT ) 3, while 3D band shows negligible renormalization. Moreover, states also display dispersion anomaly higher binding energy, reminiscent waterfall feature kinks observed cuprates.

Language: Английский

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Cuprate-like electronic structures in infinite-layer nickelates with substantial hole dopings

National Science Review, Journal Year: 2024, Volume and Issue: 11(8)

Published: June 4, 2024

ABSTRACT Superconducting infinite-layer (IL) nickelates offer a new platform for investigating the long-standing problem of high-temperature superconductivity. Many models were proposed to understand superconducting mechanism based on calculated electronic structure, and multiple Fermi surfaces orbitals involved create complications controversial conclusions. Over past five years, lack direct measurements structure has hindered understanding nickelate superconductors. Here we fill this gap by directly resolving structures parent compound LaNiO2 La0.8Ca0.2NiO2 using angle-resolved photoemission spectroscopy. We find that their consist quasi-2D hole pocket 3D electron at Brillouin zone corner, whose volumes change upon Ca doping. The surface topology band dispersion closely resemble those observed in hole-doped cuprates. However, cuprate-like exhibits significantly higher doping compared cuprates, highlighting disparities states phase. Our observations highlight novel aspects IL nickelates, pave way toward microscopic family its

Language: Английский

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Superconductivity in Freestanding Infinite‐Layer Nickelate Membranes

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(31)

Published: June 7, 2024

Abstract The observation of superconductivity in infinite‐layer nickelates has attracted significant attention due to its potential as a new platform for exploring high‐ T c superconductivity. However, thus far, only been observed epitaxial thin films, which limits the manipulation capabilities and modulation methods compared two‐dimensional exfoliated materials. Given exceptionally giant strain tunability stacking capability freestanding membranes, separating superconducting from as‐grown substrate is novel way engineer uncover underlying physics. Herein, this work reports synthesis La 0.8 Sr 0.2 NiO 2 membranes (), emphasizing crucial roles interface engineering precursor phase film growth quick transfer process achieving This offers versatile investigating nickelates, such pairing symmetry via constructing Josephson tunneling junctions higher values high‐pressure experiments.

Language: Английский

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Topochemical Synthesis and Electronic Structure of High-Crystallinity Infinite-Layer Nickelates on an Orthorhombic Substrate

Nano Letters, Journal Year: 2025, Volume and Issue: 25(3), P. 1233 - 1241

Published: Jan. 9, 2025

Superconductivity in infinite-layer nickelates has stirred much research interest, to which questions regarding the nature of superconductivity remain elusive. A critical leap forward address these intricate is through growth high-crystallinity nickelates, including "parent" phase. Here, we report synthesis a high-quality thin-film nickelate, NdNiO2. This achieved perovskite precursor phase (NdNiO3) superior crystallinity on NdGaO3 substrate by off-axis RF magnetron sputtering and low-temperature topochemical reduction using NaH. We observe nonlinear Hall effect at low temperatures this "non-doped" further study electronic properties advanced X-ray scattering first-principles calculations. spectroscopic indications enhanced two-dimensionality reduced hybridization Nd 5d Ni 3d orbitals. These findings unlock new pathways for preparing provide insights into intrinsic features compounds.

Language: Английский

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Experimental Progress in Superconducting Nickelates

Annual Review of Condensed Matter Physics, Journal Year: 2023, Volume and Issue: 15(1), P. 305 - 324

Published: Dec. 6, 2023

The superconducting nickelates were first proposed as potential analogs to the cuprate unconventional superconductors in 1999, but it took twenty years before superconductivity was successfully stabilized epitaxial thin films. Since then, a flurry of both experimental and theoretical efforts have sought understand similarities differences between two systems how they manifest macroscopic normal state properties. Although cuprates indeed share many commonalities within their respective phase diagrams, several notable also emerged, especially regarding parent compounds, electronic hybridization, fermiology. Here, we provide survey rapidly developing landscape layered nickelate superconductors, including recent progress probe not just other ordered phases these compounds.

Language: Английский

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Two-Gap Superconductivity and the Decisive Role of Rare-Earth d Electrons in Infinite-Layer Nickelates

Physical Review Letters, Journal Year: 2024, Volume and Issue: 133(12)

Published: Sept. 17, 2024

We present a theoretical prediction of phonon-mediated two-gap superconductivity in infinite-layer nickelates Nd_{1-x}Sr_{x}NiO_{2} by performing ab initio GW and perturbation theory calculations. Electron self-energy effects significantly alter the characters two-band Fermi surface enhance electron-phonon coupling, compared with results based on density functional theory. Solutions fully k-dependent anisotropic Eliashberg equations yield two dominant s-wave superconducting gaps-a large gap band rare-earth Nd d interstitial orbital small transition-metal Ni character. Increasing hole doping induces non-rigid-band response electronic structure, leading to rapid drop T_{c} overdoped regime agreement experiments.

Language: Английский

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Extensive hydrogen incorporation is not necessary for superconductivity in topotactically reduced nickelates

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Aug. 27, 2024

Abstract A key open question in the study of layered superconducting nickelate films is role that hydrogen incorporation into lattice plays appearance state. Due to challenges stabilizing highly crystalline square planar films, are prepared by deposition a more stable parent compound which then transformed target phase via topotactic reaction with strongly reducing agent such as CaH 2 . Recent studies, both experimental and theoretical, have introduced possibility from may be critical for superconductivity. In this work, we use secondary ion mass spectrometry examine La 1− x X NiO / SrTiO 3 ( = Ca Sr) Nd 6 Ni 5 O 12 NdGaO along non-superconducting NdNiO (Nd,Sr)NiO We find no evidence extensive across broad range samples, including films. Theoretical calculations indicate broadly energetically unfavorable these systems, supporting our conclusion not generally required achieve state square-planar nickelates.

Language: Английский

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Enhancement of superconductivity in Sr1−xEuxCuO2+y

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(3)

Published: Jan. 3, 2025

We report transport measurements of infinite-layer cuprate Sr1−xEuxCuO2+y films with controlled electron (by trivalent europium) and hole interstitial apical oxygen) carriers grown on SrTiO3(001) molecular beam epitaxy. An unusual enhancement superconductivity upon the moderate coexistence in is found, which spans over whole superconducting phase diagram becomes more prominent underdoped regime. The exhibits a two-dimensional nature thickness approximately 5.2 nm, irrespective varying carriers, confirmed by angle-resolved magnetoresistance Berezinskii-Kosterlitz-Thouless transition. Nevertheless, coexisting enlarge thermal activation energy vortex motion that deviates obviously from usual logarithmic evolution magnetic field. Our results offer promising perspective to understand enhance high-temperature cuprates. locked icon Physics Subject Headings (PhySH)MagnetoresistanceSuperconductivityCupratesSuperconductorsThin filmsResistivity

Language: Английский

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